Top 20 Python Interview Questions For Data Analyst

Top 20 Python Interview Questions For Data Analyst

1. What is Python? How is it different from other programming languages?

Python is a high-level, interpreted programming language that is easy to learn and use. It is different from other programming languages because it emphasizes code readability and simplicity.

2. What are the different data types in Python? How are they used?

The different data types in Python include integers, floating-point numbers, complex numbers, strings, booleans, lists, tuples, sets, and dictionaries. These data types are used to store and manipulate different types of data in Python.

3. What is PEP 8? Why is it important?

PEP 8 is a set of guidelines for writing Python code that improves its readability and maintainability. It is important because it helps ensure that Python code is consistent and easy to understand.

4. What is NumPy? How is it used in data analysis?

NumPy is a Python library for numerical computing. It is used in data analysis because it provides support for large, multi-dimensional arrays and matrices, as well as a variety of mathematical functions that are useful for data analysis.

5. What is Pandas? How is it used in data analysis?

Pandas is a Python library for data manipulation and analysis. It is used in data analysis because it provides support for data manipulation, cleaning, merging, and aggregation, as well as powerful data structures for storing and manipulating data.

6. What is Matplotlib? How is it used in data analysis?

Matplotlib is a Python library for creating visualizations and plots. It is used in data analysis because it provides a wide range of tools for creating different types of plots and charts, including scatter plots, histograms, and line plots.

7. What is Scikit-learn? How is it used in data analysis?

Scikit-learn is a Python library for machine learning. It is used in data analysis because it provides a wide range of tools and algorithms for classification, regression, clustering, and other types of machine learning tasks.

8. How do you handle missing values in a data set using Python?

There are several ways to handle missing values in a data set using Python, including dropping the missing values, imputing the missing values with a value derived from the other values in the data set, or using machine learning algorithms to predict the missing values.

9. What is the difference between a list and a tuple in Python?

The main difference between a list and a tuple in Python is that a list is mutable, while a tuple is immutable. This means that the elements of a list can be changed, while the elements of a tuple cannot.

10. What is the difference between a function and a method in Python?

A function is a block of code that performs a specific task and can be called from anywhere in the program, while a method is a function that is associated with a specific object or class and can only be called from that object or class.

11. How do you import a module in Python?

You can import a module in Python using the "import" statement, followed by the name of the module. For example, "import pandas" imports the pandas module.

12. What is the difference between shallow copy and deep copy in Python?

A shallow copy of a Python object creates a new object that references the same memory location as the original object, while a deep copy creates a new object with its own memory location and copies all the values of the original object.

13. What is a lambda function in Python? How is it used?

A lambda function in Python is a small, anonymous function that can be defined inline without a name. It is also known as a "single-use" function because it is not defined with a formal name and can only be used once. The syntax of a lambda function consists of the keyword "lambda", followed by the function parameters and a colon, and then the expression to be evaluated. 

lambda x , y : x + y

The above lambda function takes two parameters x and y, and returns their sum. Lambda functions are often used when you need to define a small function for a specific task and do not want to define a separate named function. Lambda functions are typically used with built-in functions like map(), filter(), and reduce() to perform data manipulation tasks in Python.

14. What is the difference between map() and filter() functions in Python?

The map() function applies a function to each item in an iterable and returns a new iterable with the results, while the filter() function applies a function to each item in an iterable and returns a new iterable with only the items that meet a specified condition.

15. What is a generator function in Python? How is it used?

A generator function is a special type of function in Python that can be used to generate a sequence of values on-the-fly, without storing them all in memory at once. It is used to generate large sequences of values that would be too memory-intensive to store in memory at once.

16. How do you handle exceptions in Python?

You can handle exceptions in Python using a try-except block. The code in the try block is executed, and if an exception occurs, the code in the except block is executed. You can also use the finally block to specify code that should always be executed, whether an exception occurs or not.

17. How do you use regular expressions in Python?

You can use regular expressions in Python by importing the re module and using the functions and methods provided by the module. Regular expressions are used to search for and manipulate text data based on specific patterns.

18. What is the difference between a set and a frozenset in Python?

A set is a mutable, unordered collection of unique elements, while a frozenset is an immutable, unordered collection of unique elements. This means that the elements of a set can be changed, while the elements of a frozenset cannot.

19. What is the purpose of the init method in Python classes?

The init method is a special method in Python classes that is used to initialize an object's attributes when the object is created. It is called automatically when an object is created and can be used to set default values for attributes or perform any other initialization tasks.

20. What is the difference between a class method and an instance method in Python?

A class method is a method that is associated with a class rather than an instance of the class, and can be called from the class itself or any instance of the class. An instance method is a method that is associated with an instance of a class, and can only be called from that instance.